106 thoughts on “Finally. A Working JetPack”

Previous jetPacks was so bulky they were not really jetPacks or was more rocketPacks using stuffs like hydrogen peroxid had a fly time of at most 1 or 2 minutes and were some sort of bomb strapped on your back.
I am quite surprised of the size of the motors. They seem very small for the use.
Yves Rossy device https://en.wikipedia.org/wiki/Yves_Rossy use 4 motors of the same size and need a wing for sustentation.
The first flying device used two motors but was not able to climb even with the assistance of the wing.
Maybe they “supercharged” the motors but there life time must be ridiculous.

We must remember que a tubojet twice the size does pack more than twice the power. Rossi uses somewhat small RC turbines, @1:41, we can see that one of the turbines is really big, I’d say 200mm in diameter. That’s quite big as RC turbines go.
Also, you can’t really supercharge a turbine, if you run it over it’s rated power, you are going to melt the turbine, really really fast. (in like tens of seconds fast)

What do you mean you can’t supercharge a turbine? In a gas turbine/jet engine it already is supercharged (fed by pressurised air) :P
Also, you can tun a turbine past it’s nominal design power (the GE90-115B turbofan broke a world record like that, running well past it’s design specification), it’s just that getting more gas to push the turbine more usually means making it hotter (which tends to make the turbine look like something chewed on it :D)…
But if you use a different compressor and combustor design, you can run a turbine “supercharged”, it’ll just probably be less efficient and unstable at lower power…

Last but not least, almost nothing in nature scales linearly, twice the size is very unlikely to have (just) twice the power, especially in small jet engines. Bigger engine likely means it can be more intricately designed and made, so my guess is waaaay more the 2x the power.

If this is true, then yes, there is something new: autonomy. The one you say uses hydrogen peroxide and has an autonomy of only 31 seconds. This one seems to use true turboreactors, which would allow (if it is true) a much better autonomy.

I think you may be confusing the Bell Jet Belt with the Bell Rocket Belt. The rocket belt was fueled with hydrogen peroxide and had a flight duration of 21s where as the Jet belt was powered with turbojet engines running of kerosene and could theorectically fly for 25 mins.

One of the videos on youtube ( https://www.youtube.com/watch?v=p1Oi73wGhyc ) says that this uses kerosene as a fuel. And the JB 9 has two vectored jet engines, and can run for 10+ minutes depending on pilot weight. So it is not impossible. It would suggest that the video was edited together from several different flights.

There are several scenes with and without the selfie stick mounted on “fuel tank”. The green boat in the lake is also occupied in one scene, but not in others.

The controls looks rather simple:
Pitch is controlled by tilting the engines collectively on a horizontal pivot across his shoulders. Turning looks like it´s the left handle twisting? Throttle is the right handle, so how does he bank? Varying the throttle differentially is slow on jet engines, so I guess they omitted it. So he has up/down, turn right/left and fwd/rev.

The fart in the phonebooth in the vid is the obvious tether ring visible over the pilot’s shoulder in the last few secs… OK, Tethered flight makes sense for safety when testing, but that is a heavy enough ring that _I_ would remove it for free flight.

Obviously a composition vid, which in and of itself is not bad….

Most of the shots look remarkable pendular however, as if he’s dangling like a plumb bob on a line…

Two strands of 550 cord would support that weight, maybe even one, and all the shots are over water, so if the line fails, the pilot has a (reasonably) soft landing from not too great a height.

Try this one. about 6mins and all in one shot. Looks like they have cracked it. I would expect with the sort of tech used to stabilize a drone, most of the hard work of keeping it upright will have been done. The big problem with the Bell Jet Belt was the heat of the exhaust. From what I have read and seen of that they had to keep the max thrust down so as not to burn the pilots legs!

I think this might be the first jetpack that uses an actual turbojet engine for thrust – the others all use some kind of rocket or ICE-powered ducted fans AFAIK (there’s also a flying “hoverboard” that uses propellers powered by electric motors). This thing has two jets that look similar to the ones used on Yves Rossy’s powered wing, but bigger. His jet-wing produces about 200lbs of thrust total with those 4 smaller jets.

The only thing that’s hard to believe here is that somebody flew a jetpack around the Statue of Liberty and nobody noticed :-\

The “P400-RX-G” – A turbine that costs around 11k Euros and has a weight of 3.5 Kilos can produce nearly 400N trust. take two of these and you have 800N tops. That could lift around 81 Kilos. Sounds realistic enough to work

0:30 & 0:33 possible editing at the ring on the helmet…missing sticker(or markings)
i would suggest that the trajectories are circular and in straight lines indicating hanging from a line and moving across a zip line…probably a functioning simulation of a jet pack mixed with zip lines attached to heavy equipment. cant wait to see the truth! great video!

As stated, Rocket and Jet Packs have been around since the 1960 with the US investigating and comissionings protypes back then. The most successful of these early Jet Packs was The Bell Jet Flying Belt (wingless) built in 1969 and had provisions to be able to fly for around 25mins. Project was axed though when the military reliased that the Helicopter was a far better solution for moving soliders around the battlefield.

Agreed. Look at the Bell jet belt, which had a flight time of over 30 minutes. A working turbofan based jetpack that was created around the same time as the Bell Rocket belt (the famous one) with a flight time of only about 30 seconds. It’s not really an issue of whether it’s possible, but whether it’s feasible/safe for people to use them.

Let’s see here, a PD-41 (one of the vertical lift engines for a Yak-141) weighs 290kg (639 lb) and produces 41.7 kN (9,300 lbf), over 4 tons of trust, over 14:1 thrust to mass ratio. That was made in the early 80s. By the Soviets.
Why wouldn’t a western engine made 30 years later do AT LEAST the same? Scale it down about 20 times and there’s your jet pack jet engines, the thrust/weigh ratios are well within the realm of doable.

Because the Russians are really good at metallurgy. You see, our approach is to simulate a lot of stuff. Their approach is also to do the simulations – in real life. They simply approached the problem by actually trying to make a hell lot of alloys an analyzing their properties. First, having huge sample size, they could refine their understanding of the alloys and the understanding of the physics behind. It is also like doing LMS optimization of a system you don’t know much about – you tweak and follow the gradient. The end result is that the Russians have really developed metallurgy.

No spray, but there is a disturbance that can be seen after he passes by… at about 0:59.5. 1) he’s moving forward relatively quickly (so not as much thrust focused in a single spot), and 2) he may be a little higher than during the hover/spray shots

Two things really scream “not real”
First, around the one min mark of that video… he is suddenly no longer disturbing the water as he flies over it.

The real elephant in the room comes at the very end of the video. As he is landing, he has the appearance of someone being lowered by cable(which is presumably why he has that massive ring on the top of the pack), rather than dealing with the abrupt cutoff of lift from the pack powering down.

As for “they flew it around the Statue of Liberty for a promo” that is probably the biggest give away that it is faked. They won’t let you take a pocket knife onto the island, and it is loaded with armed security(much of which you will never see). And they are telling us they got permission to fly their manned aircraft around there?The FAA is making us register 1lbs ‘drones’ for flying around picnic spots… no way they would let an unlicensed experimental aircraft do test flights in restricted federal airspace.
Just saying.

He does disturb the water at the ~1 min mark… a disturbance can be seen in the water after he passes by… at about 0:59.5. That is probably because 1) he’s moving forward relatively quickly (so not as much thrust focused in a single spot), and 2) he may be a little higher than during the hover/spray shots

Its really hard to use the absence of the gopro as evidence that its faked. They obviously put a lot of effort into producing a video, as opposed to just filming a test flight. If I were creating a video like this, I would probably just shoot multiple flights in a row: one with camera on the ground, one with the gopro on the jetpack, one with the gopro on the drone. And then just cut them together. No need to show the jetpack-mounted gopro when filming from the drone. Not saying it would be a bad thing, just that if you’re going through the trouble to make a high-end video, might as well do multiple flights and edit it with purpose.

Considering it took me about five minutes of Googling to find a random model jet engine a pair of which would be rated for about 50Kg thrust (http://www.jetcatusa.com/rc-turbines/turbine-details/p200-sx/) I’d say it’s not unthinkable they managed to come up with something that might manage twice that under specific conditions – and that would mean they’re in business. So I guest it doesn’t _necessarily_ have to be a hoax…

Did anyone see the rainbows from the mist it kicked up over the pond? It would lend some authenticity, but would also question why the difference between the first person and third person views having the go-pro mast discrepancy.

Seems like they did several different takes. Some with the gopro, some without. Some shots were filmed with a boat probably driving while some were filmed with the boat stationary (when he’s being still and just doing some thrusts)

Looking at the Statue videos, in some shots he you can see there is some heat dissipating from the engines, but when he comes in for the landing there isn’t much heat visible.

Also, those landings look pretty smooth, heck I can’t even land my quadcopter that smoothly.

I also see evidence of multiple takes. In one, the attendant with the baseball cap has a GoPro on his left side. When he steps back, it’s on his right side. At the end of the video, it’s on his left side again. As he’s coming in to land, there is a camera on a tripod by the landing pad. When you see it from 3rd person view, the camera is mssing.

The engines seem to be thrusting way out of line with the CG, so how is he hanging upright. The traditional rocketbelts bring the exhausts forward over the shoulders and thrust right in line with the shoulders/torso. These engines seem to be mounted a good 15 cm to the rear without any angling or compensation for out of line thrust.

These appear to be the biggest of JetCat’s turbines (http://www.jetcatusa.com/rc-turbines/turbine-details/p200-sx/), painted black. Each of these puts out ~45lbs net thrust (and that’s not including fuel/batteries/ECU etc), which means they’ve either goosed the engines or that’s a REALLY light pilot. NO2 is possible in turbines, but I wouldn’t want one strapped to me. That said, there is a plethora of small APUs that don’t look at all like this but can do the job.

There’s enough third party video of the Statue of Liberty flight that it’s either plausible or a truly devious social media campaign. (https://youtu.be/7M8xefdmx0g)

Hmmm. The JetCats are built as axial turbines that use turbo parts in the hot end – I wonder if they’ve goosed this kind of design up (or if JetCat’s building bigger engines for them) since the design is so similar.

I just did a quick back-of-the-napkin energy analysis. Rate of energy required to hover is mgv/2, Assuming: 150 kg total mass, and the turbines exhaust velocity is 20,000 m/s (J-58 turbojet, first turbjet number I could find), you get 14.7 MJ/s. They advertise 10 minutes flying time, so total energy needed to just hover would be 8.8 MJ. Kerosene is rated for 0.142 MJ/gal, so you’d need 62 gallons with you. The fuel alone weighs over 400 lbs, far over the my initial total mass guess. Raising my guess just makes things worse. Even if it does fly, you’ll never get 10 minutes. My exhaust velocity number may be low, but I’m really skeptical.

I found a erroneous equation that looks like you used from one of the first google hits. Looks like you (or the forum poster) are confusing mass flow with vehicle weight… You need a force balance. F=ma, with a being gravity. so F=mg. If thrust is T=v*mdot (mdot being mass flow of exhaust) and is equal to the force of gravity, then
1) mg=v*mdot but you don’t know mdot or v
2) mdot = v*A*roh where A is the jet nozzle and roh is the density of air so sub 2 into 1:
3) mg=v*v*A*roh
Now you can solve for mass flow and velocity given the mass of the person+jetpack and the nozzle diameter:
4) v = sqrt(mg/A*roh)
5) mdot = v*roh*A
And finally you can find the power used:
6) deltat=1s set a time step to 1 second
7) mdot/t=m divide mass flow by 1 second to get mass
8) K = .5*m*v^2 kinetic energy
9) P=deltaK/deltat find the power (since the air starts at 0 velocity, deltaK = K-0)

Throw this into a spreadsheet and say 100 kg pilot + jetpack, (50 per jet) and .1m (4″) nozzle diameter you get a requirement of 55 kW from each jet. 110 kW (about 150 hp) to hover sounds reasonable…

Hmm. Always nice to work from measured engineering data: looked up the JetCat performance tables (http://www.jetcatusa.com/images/Engine%20Data%20Sheet%207-14-2015.pdf) and look at thrust vs. fuel consumption. The thrust to fuel consumption ratio is pretty close to constant, so it looks like you can simply scale. But just assuming two of the top turbines, you have 2×89 pounds of thrust, for a total of 178 pounds thrust, at a fuel consumption rate of 2×1.3 = 2.6 liters/minute or 0.68 gallons/minute. That means ten minutes of flight time would require 6.8 gallons of fuel, or 21 kg = 46 lbs of fuel for a ten minute flight. Five minutes for three and a half gallons, etc.

(Though if the backpack in the photos is almost entirely fuel tank, that could work out.)

That’s using conservative numbers for the thrust and the like. I weigh about 150 lbs, with gear that would easily bump up to 170, which leaves me little if any leeway for fuel. Oh, and if I’m using this kind of thing for real I want a parachute of some sort so I don’t turn into a grease spot on the pavement in the event of an equipment failure.

This also doesn’t address the question of reliability if you run your turbines at full thrust continually. And that’s just for hover, so you get no forward motion without noticeable loss of altitude.

Maybe works, but I’m skeptical of some of the claims. This might work OK, but only give you a few minutes of flight time. That would still be really cool though: parts seem to be readily available (if pricey) and the fuel is cheap and available everywhere.

The videos are real. This summer 2015 we conducted our first untethered flights over water after years of testing on a safety tether through all the iterations (during the past 25 years). The reason the JetPack is called JB-9 is because this is the 9th iteration (JB stands for JetBelt). David made 3 amazing flights that day. It flew spectacularly, better than expected. On flight #2 I placed a GoPro HERO 4 on the left side of his helmet. On flight #3 we added another GoPro HERO 4 on a 5ft long JetPack-Selfie-Stick (pole) off the rear of the pack facing down to get that bird’s eye view of David and the JetPack flying. The video edit never used ground or drone footage from flight #3 when we had the long unsightly GoPro selfie-stick attached to the rear of the pack. This has been 76 years in the making for Nelson Tyler, the first civilian to build a RocketBelt (the one that Bill Suitor flew in the 1984 Los Angeles Olympics Opening Ceremonies), and inventor/designer of the JB-9 (and the WetBike, Helicopter stabilized camera mounts, and so much more).

The difference you see in the water disturbance at 0:57 is because he had picked up a lot more forward thrust by pushing down on the control arms. The whole engine assembly tilts in accordance to whether he’s pushing down or pulling up on the control arms. You can see around 1:01 him pull up on the control arms to slow down his forward speed. You’ll see more water spray across the board when he his “hovering” or moving slowly than when he’s accelerating due to the engine angle against the water.

If you look at the drone shot (taken by me) you can see that there is still water displacement, it’s just less, and much farther behind him. (start around 1:42) https://youtu.be/ODkKOP7K1w4?t=1m42s

Not sure why it’s often forgotten, but in 1984 Olympics in Los Angeles. The opening ceremony featured the arrival of Bill Suitor by means of the Bell Aerosystems rocket pack (also known as a Jet Pack).

Look it up, a working Jet Pack. Bill Suitor flew into a full stadium with it.

On the shots with the go-pro on a stick it’s not showing on the shadow and it should since it’s way back and above over hes head. And in ther statue of liberty video when he takes of on 0.16 instead of taking of forward or straight up hes got an right curve on hes trejectory much like beigh hung from a boom that starts rapidly turning arround it’s axis. NY vid here https://www.youtube.com/watch?v=gCYSWyHDpfU

Rather simple controls they seem to have:http://jetpackaviation.com/wp-content/uploads/2015/10/jpa001.jpg
Looks like 2D differential trust vector control. Tilt both nozzles forward/backward to go forward/backward. Tilt them in opposite direction to turn left/right. What I don’t understand is how they control rolling. AFAIK turbines take rather long to spin up/down, thereby differential trust is rather slow => takes long time to correct roll error.
Maybe the small inverted V alignment of the turbines is enough to correct for that, but I’m not sure how reliable that is

The FAA approved flight around Statue of Liberty – so obviously they must have seen it fly – its the real deal for sure – I don’t think someone who has 3 academy awards for engineering will put his name on a fake – a producer might LOL but not an engineer like Nelson Tyler

I’ll be the first to mention the Williams X-Jet (aka WASP II) of the 1980s and its 1970’s predecessor the WASP, Williams Aerial Systems Platform. How about a 45 minute flight time and 75 MPH speed?

The US military is decommissioning some older cruise missiles that used the same engines as those, I wonder if they’re selling the engines intact or “demilled” scrap?

A modern WASP or X-Jet could take advantage of much lighter weight composite materials to further extend its flight duration/range or carry more load. I think the military missed a very useful vehicle. A couple hundred of these, with machine guns and rocket launchers on their sides, would make for some high speed infantry occupation tactics. At the least some RTS game should include them.

In one episode of “Auction Hunters” they come across a cruise missile jet engine in a storage room. They sell it off to a RC jet fanatic, so possible yes. If you are an US citizen. Export restrictions applies for sure.

I find it disturbing to read some of the comments here. They have done a really great job to built that JetPack. Some self announced experts want to question that. I could now argue with those about why it is real but I don’t waste that time. Maybe some of the guys who where saying that is fake should have a look here: http://www.amtjets.com/specs.php

The Williams Research fanjet used in the Tomahawk cruise missiles has a roughly 50% higher thrust than the man rated versions – but has a time between overhauls of 15 hours. Not very useful for human flight! But then again, that was with fanjet technology of the 1960s and 1970s.

Also, for thrust calculation, use the BSFC numbers – 5 pounds of fuel per pound of thrust for crude pulse jets and other hobby efforts; 2 for simple fanjets, well under 1 for (big) state-of-the-art multispool high bypass controllable pitch compressor designs. So, assuming SWAG BSFC of 2 with a 250 pound gross weight for 10 minutes with 7 pound per gallon kerosene gives 2*250/(7*10) or about 7 gallons – in the ballpark of the above calculations.